Api publ 4645 1997 scan (american petroleum institute)

AUSTIN, TEXAS 7859 JANUARY 1997 American Petroleum Institute Copyright American Petroleum Institute Provided by IHS under license with API Not for Resale No reproduction or network

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S T D n A P I I P E T R O P U B L 4 b 4 5 - E N G L 1 9 9 7 0 7 3 2 2 9 0 0 5 b 3 3 9 0 b 9 7 a31

American Petroleum Institute

Health and Environmental Sciences Department

Publication Number 4645 January 1997

Copyright American Petroleum Institute

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`,,-`-`,,`,,`,`,,` -S T D A P I / P E T R O P U B L LIb45-ENGL 1797 0 7 3 2 2 7 0 ( 3 5 b 3 3 9 1 5 2 5

Methane and Carbon Dioxide Emission Estimates From US Petroleum Sources

Health and Environmental Sciences Department

API PUBLICATION NUMBER 4645

PREPARED UNDER CONTRACT BY:

MATHEW R HARRISON, P.E

THERESA M SHIRES RADIAN INTERNATIONAL LLC

8501 N MOPAC BLVD

AUSTIN, TEXAS 7859

JANUARY 1997

American Petroleum Institute

Provided by IHS under license with API

Not for Resale

No reproduction or networking permitted without license from IHS

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FOREWORD

API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL NATURE WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE,

AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED

API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS, MANUFAC- TURERS, OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIP THEIR EMPLOYEES, AND OTHERS EXPOSED, CONCERNING HEALTH AND SAFETY

LOCAL, STATE, OR FEDERAL LAWS

NOTHING CONTAINED IN ANY API PUBLICATION IS TO BE CONSTRUED AS GRANTING ANY RIGHT, BY IMPLICATION OR OTHERWISE, FOR THE MANU- FACTURE, SALE, OR USE OF ANY METHOD, APPARATUS, OR PRODUCT COV- ERED BY LETTERS PATENT NEITHER SHOULD ANYTHING CONTAINED IN ITY FOR INFRINGEMENT OF LEïTERS PATENT

THE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL-

Copyright O 1997 American Petroleum Institute

111

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COMPARISON OF METHODOLOGIES 2.1

STANDARD APPROACH 2.2 LITERATURE REVIEW 2-2 KEY ELEMENT COMPARISONRANKING 2-3

Boundaries 2-3 Detail Level 2-4 Data Quality 2.15 Representativeness 2-18 Comprehensiveness 2-19 Practicality 2.25 CONCLUS IONS 2.26

METHODOLOGY FOR PROJECTIONS TO 2000 4.1

METHODOLOGY FOR METHANE ACTIVITY FACTOR PROJECTIONS 4.1

Production 4-1 Crude Transportation 4-2 Refining 4-3 Product Transportation 4-3 Mass Balance 4-3

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TABLE OF CONTENTS (Continued)

METHODOLOGY FOR CO ACTIVITY FACTOR PROJECTIONS 4.5

Production 4-5 Crude Transportation 4-5 Refining 4-6 Product Transportation 4.6 METHODOLOGY FOR EMISSION FACTOR PROJECTIONS 4.7

Oil and Gas (O&G) Production MACT 4-8 Marine Vessel Recovery (MVR) MACT 4-10 Refinery MACT 4-12 Gasoline Distribution MACT 4-14 Energy Efficiency Changes 4-15

5 EMISSIONS AT YEAR 2000 5-1

6 CONCLUSIONS 6.1

RESULTS 6.1 SENSITIVITY ANALYSIS 6-2 RECOMMENDATIONS 6-5

7 REFERENCES R-I APPENDICES

Appendix A Supporting Figures for Section 4 A-I

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Comparison of Report Detail Levels and Emission Estimates by Industry Segment 2-6

1990 CO, Emissions Summary from API: Global Emissions of Carbon Dioxide from Petroleum Sources 2-7

1990 CH, Emissions Summary from API: Global Emissions of Methane from Petroleum Sources .2-8

1990 CO, Emissions Summary for EPA: Inventory of U S Greenhouse Gas Emissions and Sinks: 1990-1993 2-9

1990 CH, Emissions Summary for EPA: Inventory of U.S Greenhouse Gas Emissions and Sinks: 1990-1993 2-9

1990 CH, Emissions Summary for EPA Report to Congress:

Anthropogenic Methane Emissions in the United States 2-1 O

CH, Emissions Summary for IPCC (No Base Year Specified): Greenhouse Gas Inventory Reference Manual 2-1 1

CO, Emissions Summary for IPCC (No Base Year Specified): Greenhouse Gas Inventory Reference Manual 2-1 1

CH, Emissions Summary for E&P Forum (No Base Year Specified):

Methods for Estimating Atmospheric Emissions from E&P Operations 2-12

CO, Emissions Summary for E&P Forum (No Base Year Specified):

1992 CH, Emissions Summary for GRI/EPA Study: Methane Emissions

2-1 4

Ranking of EF Data Quality 2-16 Ranking of AF Data Quality 2-16 Total Study Summary Comparison of Representativeness,

Comprehensiveness and Practicality 2-20 Production Segment Comparison of Representativeness,

Crude Transportation Segment Comparison of Representativeness,

Refining Segment Comparison of Representativeness, Product Transportation Segment Comparison of Representativeness, Table 3-1 API 1990 Methane Emission Estimate for Methane Based on

Methods for Estimating Atmospheric Emissions from E&P Operations 2-1 3

from the Natural Gas Industry (Multiple Reports)

Comprehensiveness and Practicality 2-21

Comprehensiveness and Practicality 2-22 Comprehensiveness and Practicality 2-23 Comprehensiveness and Practicality 2-24 the IPCC Methodology 3-2

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Petroleum Mass Balance MM Tons/yr 4-4

Crude Handling Activity Factor Comparison for CO, 4-5

Carbon Dioxide Emission Projections for 2000 5-3 Methane Emission Projections Activity Factor Sources 5-4 Methane Emission Projections Emission Factor Sources 5-4 Carbon Dioxide Emission Projections Activity Factor Sources 5-5

Product Transport Activity Factor Comparison for CO 4-6

Methane Emission Projections for 2000 5-2

Carbon Dioxide Emission Projections Emission Factor Sources 5-6 Estimated and Projected Emissions from the Petroleum Industry (Million

Tons peryear) 6-4

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`,,-`-`,,`,,`,`,,` -EXECUTIVE SUMMARY

The United States Environmental Protection Agency (EPA) and others have previously estimated United States emissions of greenhouse gases, including the contribution from the United States petroleum industry This has led the United States petroleum industry to conduct this more refined estimate of its emissions of carbon dioxide (CO,) and methane (CH,) for the base year of 1990 and to project those emissions to the year

Estimation of emissions for the year 2000

Tasks 1 and 2 were based upon reviews of existing greenhouse gas inventory

literature, and Tasks 3 and 4 were based upon review and use of available published

data showing activity and emission projections Emission estimates for a given time period are calculated by multiplying an emission factor (e.g., units of mass emissions per volume throughput) by an activity rate (e.g., units of volume throughput per time period)

API previously estimated global emissions of carbon dioxide and methane from

petroleum sources in reports issued in 1991 -1 992 This report updates those estimates for the exploration and production, crude transportation, refining, and product

transportation segments of the United States petroleum industry The approach used

ES-I

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in this study represents the best available approach for the level of emissions and activity data that is publicly available This approach is preferable to the United Nation’s IPCC methodology for calculating national estimates of greenhouse gas emissions for two reasons:

1)

2)

It is specific to the petroleum industry; and

It includes some source categories which are omitted in the IPCC methodology

RESULTS

Existing greenhouse gas emissions literature was reviewed, examining the following key parameters: boundaries, detail level, representativeness, comprehensiveness, data quality, and practicality None of the existing studies reviewed were found to be ideal for estimating emission rates for the U.S petroleum industry, but a best estimate approach was developed using the IPCC methodology as a basis with supplemental estimates from the other studies examined Methods for estimating (year 1990) and projecting (year 2000) activity factors for the petroleum industry were developed based

on the literature Projected changes to emission factors resulting from implementation

of proposed regulations as well as energy efficiency improvements were also identified

Table ES-1 presents the estimated and projected methane and CO, emissions from the U.S petroleum industry The total year I990 emissions of CO2 from petroleum

production through product transport are 284 million tons, which compares reasonably

well with the estimate in the previous API report of 300 million tons The differences can be attributed to updated activity factors for the production and transportation industry segments, and to accounting for actual refinery utilization in determining the year 1990 refinery activity factors The CH, emissions of 0.848 million tons for 1990

may be contrasted with an estimate of 0.392 million tons in the previous API study The difference in the methane estimates can be attributed to the inclusion of production tank emissions and the use of updated activity factors in this study

ES-2

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Table ES-I Estimated and Projected Emissions of Greenhouse Gases from the

Total carbon dioxide emissions are projected to increase slightly from 284 million tons

in 1990 to 288 million tons in the year 2000 Emissions of CO2 are projected to

decrease in the crude transport segment, but increase slightly in the other industry segments Projected annual emissions of methane show a reduction of 0.239 million tons over the period, This reduction occurs primarily in the exploration and production segment due to reductions in both the emission factors and the activity factor (amount

of crude produced)

The Global Warming Potentials (GWP) recommended by the IPCC and developed by other studies allow scientists to compare the ability of each greenhouse gas to trap

heat in the atmosphere relative to other gases The I 0 0 year GWP for carbon dioxide

is 1 and for methane it is 24.5 This means that each ton of methane has about 25 times more global warming impact than a ton of carbon dioxide When adjusted for GWP, Table ES-2 shows that greenhouse gas emissions (COz and CH,) from the U.S petroleum industry will decrease by 0.6% from 1990 to 2000

Table ES-2 Estimated and Projected GWP-Adjusted Emissions of Greenhouse Gases

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SENSITIVITY ANALYSIS

Most of the emission factors used in this study were developed from limited samples of emission measurements This study’s estimate could be further refined in the future if more detailed data become available No such estimates exist today, although an

ongoing study by the U.S EPA Office of Research and Development (ORD), “Mefhane

€missions from the Petroleum /ndustry,’”may provide that detail for methane in the near

future

General sensitivity examinations were conducted to examine key sources of emissions For CO2, the top four emission sources are: drilling, refinery thermal processes,

refinery atmospheric separation, and catalytic hydrorefining The activity factors for

these categories are expected to be fairly constant over the ten year period examined

in this study, and the emission factors from these sources are known with a reasonable level of certainty Therefore, the CO, estimates in this study do not appear to be very sensitive to the assumptions made

The general sensitivity examination for methane revealed that the largest single

emission source is production tanks and the second largest is production “fugitives,

maintenance, and venting & flaring.” These two sources dwarf the emission estimates for the other industry segments Regarding the sensitivity examination:

The emission estimate is not performed on an equipment level of detail and therefore has some inherent uncertainties

o The activity factor for these sources is production rate which is

somewhat uncertain for the year 2000

o There is considerable uncertainty as to the absolute level of the

methane emission factors for sources in these categories, but it is expected that these factors will remain flat or decline over the period due to measures being undertaken by the industry As a result, the trend in methane emissions will be flat to declining from 1990-2000

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As indicated in Table ES-2, the CO, emissions dominate the GWP-adjusted emissions

from the U.S petroleum industry Therefore, the total estimates of greenhouse gas emissions from the petroleum industry are not likely to be very sensitive to the

assumptions made, despite the greater uncertainty in the methane emissions

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`,,-`-`,,`,,`,`,,` -Section 1 INTRODUCTION

I

The objective of this project is to revise and update the methodology and inventory for methane (CH,) and carbon dioxide (CO,) emissions from the United States petroleum industry API had previously estimated global emissions of methane and carbon

dioxide from petroleum sources in reports issued in I991 -1 992 (Radian 1991 ; Radian 1992) This project focuses on emissions from the United States and updates the

estimates for the production of crude through the transport of refinery products

This effort has been divided into four tasks:

Task 1:

Task 2:

Task 3:

Task 4:

Comparison of Methodologies-This task compares the attributes

of available methodologies and the relative applicability to emissions from the U.S petroleum industry (see Section 2)

1990 Emission Estimate-To the extent possible, the methodology outlined by the Intergovernmental Panel on Climate Change (IPCC)

is used in this task to update the previous methane and carbon dioxide emission estimates for the year 1990 (see Section 3) Data from other sources are used as necessary

Selection of Methodology for Projecting Emissions-This task reviews methods for projecting U.S petroleum industry emissions

to the year 2000 and recommends an approach (see Section 4)

Estimation of Emissions for the Year 2000-Based on recommendations outlined in Task 3, this task computes methane and carbon dioxide emission estimates for the year 2000 (see Section 5)

PETROLEUM INDUSTRY BOUNDARY DEFINITION

Boundaries define what is considered the "petroleum industry" and can exclude certain equipment that is not directly related to the petroleum industry Boundaries must be

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established for the petroleum industry that are technically reasonable, and that match the boundaries used by other accepted U.S studies such as the GRI/EPA methane

emissions study for the natural gas industry (Radian, 1996)

The petroleum industry can be broken into distinct segments so that data from existing

reports can be compared on a consistent basis, and so that segments excluded by

certain reports become more readily apparent Based upon examination of existing

emission estimates, the following four segments provide the most consistent approach:

1) Production (exploration/extraction)-This includes all well and

surface production equipment, including storage tanks associated with domestic crude production;

2) Crude transportation-This includes all truck, marine, rail, and

pipeline transportation of crude, including imported crude;

3) Refining-This includes crude storage tanks, all refinery units, and

finished product tanks;

4) Product transportation-This includes all transport of refinery

products by truck, marine, rail, and pipelines

Figure 1-1 shows a simplified conceptual diagram of these industry segments

Because oil and gas can be produced from the same well, the production segment

presents some interesting boundary issues, where some equipment may be related

solely to natural gas production, and therefore may not be part of the petroleum

industry Figure 1-2 shows the production sector boundary definitions as defined in the GRI/EPA methane emissions study (Radian, 1996a) The GRVEPA study of methane emissions from the natural gas industry deals with the production boundary issue on an equipment level detail Although the GRVEPA report specified the natural gas industry boundaries, by inference all items outside of the gas industry boundaries are petroleum industry equipment Experts from API member companies participated in determining

1-2

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Field Use Gas

Vapor Recovery

Compressor

Condensace

or Oil Tank Control Valve Petroleum Industry

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the boundary definition used in the GRVEPA report Therefore this report recommends

the production boundaries shown in Figure 1-2

All downstream equipment in crude transportation are included within the petroleum

industry boundaries

Refining includes all refinery equipment and tanks (crude and product tanks)

Aromatics and isomerization processes in refineries are also included However, the

refinery boundary excludes the downstream chemical plant operations such as steam

cracking ethylene plants, plastic/rubber operations, etc., even though these operations

may sometimes be integrated within a refinery complex The refinery boundaries are

consistent with those used by The Oil and Gas Journal for reporting refining activities

(Thrash, 1991)

Product transport includes all refinery fuel products, but similar to the refining segment,

it excludes chemical plant products

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`,,-`-`,,`,,`,`,,` -Section 2 COMPARISON OF METHODOLOGIES

The strengths and weaknesses of various recommended methodologies for estimating methane and carbon dioxide emissions from the petroleum industry are compared in this section This effort centers on the comparison of other, more recent methodologies and inventories to the earlier API reports on greenhouse gas emissions:

API Global Emissions of Methane from Petroleum Sources (Radian, 1991)

API Global Emissions of Carbon Dioxide from Petroleum Sources (Radian,

Guidelines for National Greenhouse Gas Inventories,

Volumes 1 through 3 (IPCC, 1995)

Methods for Estimating Atmospheric Emissions from E&P Operations (E&P 1994)

Methane Emissions from the Natural Gas Industry

Multiple reports (Radian, 1996)

2-1

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In the following portions of this text, the eight reports listed above will be referred by the following names: API CH, report, API CO, report, EPA Greenhouse report (a), EPA RTC (b,c), IPCC report, E&P Forum report, and GRI/EPA reports, respectively

LITERATURE REVIEW

The literature review for this API project was limited to the eight reports listed previously Some literature search data were available from a concurrent project, however, very few of these sources produced overall methodology data API directed that the reports listed in the original proposal should be the main focus for this

evaluation (API CO, report, API CH, report, EPA reports, IPCC report, E&P Forum report, and GRUEPA reports) In a few instances, other reports were evaluated for

specific equipment source references; these reports are mentioned in the following sections

2-2

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KEY ELEMENT COMPARISON/RANKING

The methodology analysis culminated in a comparison of key elements or parameters

These key elements are: boundaries, detail level, representativeness,

comprehensiveness, data quality, and practicality:

At what level were the emission calculations made (¡.e., individual equipment emission factors, or

single factors for an entire segment)?

Were data generated specifically for the U.S

petroleum industry or extrapolated from other industries?

Did the study include all significant emission sources?

What was the quality of the data used in the study

(¡.e., test results or engineering judgement)?

Can the technique be applied by industry, considering current data limitations?

The criteria established for each of these ranking parameters is described in the

following subsections

Boundaries

The boundary (¡.e., emission sources relative to the U.S petroleum industry) adopted

by the report being evaluated was compared against the selected API petroleum

industry boundary as discussed in Section i Most of the reports, with the exception of

the GRVEPA reports, did not estimate emissions on an equipment level so distinct

industry boundaries could not be utilized This is an issue for the production segment

particularly, where some of the references report emissions that combine both oil and

2-3

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natural gas industry sources For example, the IPCC report provides only one methane emission estimate for production, which is based on both oil and gas production

activities; no method of separating oil emissions from natural gas is provided

Detail Level

Detail level refers to the extent at which the calculations were made, such that the more detail involved, the better the approach (more representative of the industry, better quality data, etc.) For example, the E&P Forum report states that calculations can be made in one of five increasingly accurate levels of detail:

Preliminary regional estimate;

Emission factor based on fuel consumption and quantity of gas vented and flared:

Application of emission factors to generic pieces of equipment;

Application of equipment specific emission factors and operational data such as load variations; and Emission data derived from direct measurement

However, many of these levels of detail are redundant or apply only to a specific site emission estimate, rather than a national estimate For example, Tier 5 is not possible for a national estimate because it is unrealistic to directly measure emissions from

every piece of equipment Therefore, the Tier 5 approach would have to be combined with Tier 3 to extrapolate measurements from representative pieces of equipment to a national emission estimate

The following tiers will be used for this API evaluation of the detail level of national

estimates:

Tier 1 : Tier 2:

Emission data from other reports of unknown quality; Approximate industry wide estimates;

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Most reports did not define the detail level at which the values were calculated

However, the detail level can be subjectively determined by review of the report Table

2-1 shows the emission estimate for each industry segment covered by the reports and

the detail level estimated by this analysis Further breakdown of report detail is

discussed in the following sections and shown in Tables 2-2 through 2-1 1 Please refer

to the reports reviewed for details on the sources and calculation techniques used

2-5

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Data Qua I ity

Data quality is a function of the detail level (described previously), as well as the basis

for the emission factors Emission factors can be determined from tenuous broad brush

estimates, reasonable data-based estimates, or field emission measurements Tables

2-12 and 2-1 3 show a matrix of data quality for emission factors and activity factors that

range from worst to best The matrix is based upon a scale of increasing detail level

and a scale of better emissioníactivity factor basis In these tables "worst" indicates

that the emission factor or activity factor estimate is generally applied to the entire

industry with poor or incomplete background information to support the estimates The

term "best" indicates that scientifically valid equipment level measurements were

performed for the emission factor and the equipment level activity factor is based on a

documented nationally tracked source For both tables, "unknown" indicates that no

documentation was provided for a particular emission factor or activity factor, so a

ranking could not be estimated

The matrix scale for data quality was used where possible to subjectively rank the data

quality of the emission factor data for each of the reports The results of this analysis

are shown in Tables 2-2 through 2-1 I The column labeled "EF Quality" gives a

subjective ranking of the data quality based upon the matrix shown in Table 2-12 For

the GRVEPA methane emissions project, 90% confidence bounds for the emission

factor terms were calculated to provide an accuracy estimate These values are listed

in the "EF Quality" column for this report

Data quality also depends on the source for the data Figure 2-1 shows the

approximate lineage for the data for each of the major reports being considered by this

analysis As shown in this diagram, the reports are inter-connected and rely on much of

the same information

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`,,-`-`,,`,,`,`,,` -Table 2-13 Ranking of AF Data Quality

orted well known

Equipment Counts (Counts of specific equipment andlor detailed activities) Refinery Unit Activity Data (based on unit counts and feed rates)

Entire Industry AF (based on total oil produced or refined)

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Rep resen tativeness

To the extent possible, representative data are data generated specifically for the

United States petroleum industry, rather than extrapolated from other industries or other countries In addition, data should represent emissions in the United States by

accounting for equipment types and operational practices specific to the United States For example, the activity factor should be based on I990 production rates and/or

equipment populations in the U.S petroleum industry Likewise, emission factors

should account for regional operating differences and pollution control devices

determining equipment specific emission factors to the level of detail used in the

GRI/EPA study, is beyond the scope of this report

In general, most of the estimates from the reports reviewed are representative, in that they deal with the petroleum industry and are based on emission estimates derived from United States data For example, the IPCC manual is designed for use by any country, but default emission factors are taken from United States sources Likewise, the E&P Forum report is published by an international organization and provides

emission data from many different countries, but emissions are provided specifically for the United States The total carbon dioxide emission estimate from the E&P Forum report, however, is based on the production of both oil and gas in the United States No overall estimate is provided specific to the oil industry in the E&P Forum report

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For the purpose of this API project, the emission estimates must be based on data representative of the United States petroleum industry An exception is the GRVEPA

reports series which is based on methane emissions from the natural gas industry

Information from the GRIIEPA report is only applicable to the production segment, but

in the production segment, equipment and operating practices associated with gas and oil wells are similar and therefore representative of emissions for this study

The representativeness of individual reports is indicated in Tables 2-14 through 2-1 8, where “J” indicates that the emission estimates are developed for the United States pet role u m industry

Comprehensiveness

A comprehensive study should consider all significant emission sources Even if the detail level is a broad brush approach (Tier I), it should include an approximation for all

significant sources Tables 2-14 through 2-18 provide an overview of the

comprehensiveness A column in these tables describes any items not covered by the particular report

Some additional details on comprehensiveness are provided in Tables 2-2 through 2-

II, which show industry segments and the individual sources calculated by each report Any industry segment that is ignored indicates a possible lack of comprehensiveness Within the segments, equipment that is identified as a major source by one study, but which is ignored by a second study, probably indicates that part of the second study is incomplete

Comprehensiveness varied from study to study, and varied within studies depending on the segment and the emission (CO, or CH,) In the production segment for CH,, the GRVEPA reports had the most comprehensive approach, since these include large emission sources ignored by other reports (pneumatics, chemical injection pumps,

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Tiêu đề	Methane And Carbon Dioxide Emission Estimates From U.S. Petroleum Sources
Tác giả	Matthew R. Harrison, P.E., Theresa M. Shires LLC, Radian International
Trường học	American Petroleum Institute
Chuyên ngành	Health and Environmental Sciences
Thể loại	Publication
Năm xuất bản	1997
Thành phố	Austin

Định dạng
Số trang	108
Dung lượng	2,85 MB